Assembling Alkaline-Responsive Chitosan@Giant Liposomes through an Ultrasound-Integrated Microfluidic Approach.

This paper presents the fabrication of an alkaline-responsive drug carrier, chitosan@giant liposome (CS-GL), by using an ultrasound-integrated microfluidic approach. On the microfluidic chip, water/oil/water droplets are first prepared and then move through an area of ultrasonic radiation to improve the regional saturation of organic solvent and accelerate its removal. At the same time, phospholipid molecules in the oil phase of the droplets are efficiently self-assembled into giant liposomes (GLs). Subsequently, microfluidic channels combined with an up-down separated structure can help in the fabrication and purification of the GLs. Due to the electrostatic interaction between the amino group of chitosan and the phosphate group of phospholipids, the GLs and chitosan are assembled into CS-GLs. The change of ζ potential after this operation indicates that chitosan is coated on the surface of GLs. The formed CS-GLs are monodispersed with a 54.1 ± 0.7 µm diameter and high drug encapsulation efficiency (∼96%), and the structural integrity can be kept without leakage of contents for more than a week in an acid medium (pH = 1.2). When this structure is placed in an aqueous solution of pH = 7.8, chitosan precipitates gradually and detaches from the GL, causing its rupture. The drug encapsulated in a single CS-GL can be rapidly released within 4 s, and 99.6% of the CS-GL carriers can complete the release within 10 min.

New Insight into Assembled Fe3O4@PEI@Ag Structure as Acceptable Agent with Enzymatic and Photothermal Properties.

Metal-based enzyme mimics are considered to be acceptable agents in terms of their biomedical and biological properties; among them, iron oxides (Fe3O4) are treated as basement in fabricating heterogeneous composites through variable valency integrations. In this work, we have established a facile approach for constructing Fe3O4@Ag composite through assembling Fe3O4 and Ag together via polyethyleneimine ethylenediamine (PEI) linkages. The obtained Fe3O4@PEI@Ag structure conveys several hundred nanometers (~150 nm). The absorption peak at 652 nm is utilized for confirming the peroxidase-like activity of Fe3O4@PEI@Ag structure by catalyzing 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. The Michaelis-Menten parameters (Km) of 1.192 mM and 0.302 mM show the higher catalytic activity and strong affinity toward H2O2 and TMB, respectively. The maximum velocity (Vmax) value of 1.299 × 10-7 M·s-1 and 1.163 × 10-7 M·s-1 confirm the efficiency of Fe3O4@PEI@Ag structure. The biocompatibility illustrates almost 100% cell viability. Being treated as one simple colorimetric sensor, it shows relative selectivity and sensitivity toward the detection of glucose based on glucose oxidase. By using indocyanine green (ICG) molecule as an additional factor, a remarkable temperature elevation is observed in Fe3O4@PEI@Ag@ICG with increments of 21.6 ∘C, and the absorption peak is nearby 870 nm. This implies that the multifunctional Fe3O4@PEI@Ag structure could be an alternative substrate for formatting acceptable agents in biomedicine and biotechnology with enzymatic and photothermal properties.

Recent Advances in Metal-Based Magnetic Composites as High-Efficiency Candidates for Ultrasound-Assisted Effects in Cancer Therapy.

Metal-based magnetic materials have been used in different fields due to their particular physical or chemical properties. The original magnetic properties can be influenced by the composition of constituent metals. As utilized in different application fields, such as imaging monitoring, thermal treatment, and combined integration in cancer therapies, fabricated metal-based magnetic materials can be doped with target metal elements in research. Furthermore, there is one possible new trend in human activities and basic cancer treatment. As has appeared in characterizations such as magnetic resonance, catalytic performance, thermal efficiency, etc., structural information about the real morphology, size distribution, and composition play important roles in its further applications. In cancer studies, metal-based magnetic materials are considered one appropriate material because of their ability to penetrate biological tissues, interact with cellular components, and induce noxious effects. The disruptions of cytoskeletons, membranes, and the generation of reactive oxygen species (ROS) further influence the efficiency of metal-based magnetic materials in related applications. While combining with cancer cells, these magnetic materials are not only applied in imaging monitoring focus areas but also could give the exact area information in the cure process while integrating ultrasound treatment. Here, we provide an overview of metal-based magnetic materials of various types and then their real applications in the magnetic resonance imaging (MRI) field and cancer cell treatments. We will demonstrate advancements in using ultrasound fields co-worked with MRI or ROS approaches. Besides iron oxides, there is a super-family of heterogeneous magnetic materials used as magnetic agents, imaging materials, catalytic candidates in cell signaling and tissue imaging, and the expression of cancer cells and their high sensitivity to chemical, thermal, and mechanical stimuli. On the other hand, the interactions between magnetic candidates and cancer tissues may be used in drug delivery systems. The materials' surface structure characteristics are introduced as drug loading substrates as much as possible. We emphasize that further research is required to fully characterize the mechanisms of underlying ultrasounds induced together, and their appropriate relevance for materials toxicology and biomedical applications.

Development of a Microfluidic Formatted Ultrasound-Controlled Monodisperse Lipid Vesicles' Hydrogel Dressing Combined with Ultrasound for Transdermal Drug Delivery System.

Transdermal drug delivery system (TDDS) has attracted much attention in the pharmaceutical technology area. However, the current methods are difficult to ensure penetration efficiency, controllability, and safety in the dermis, so its widespread clinical use has been limited. This work proposes an ultrasound-controlled monodisperse lipid vesicles (U-CMLVs) hydrogel dressing, which combines with ultrasound to form TDDS. Using microfluidic technology, prepare size controllable U-CMLVs with high drug encapsulation efficiency and quantitative encapsulation of ultrasonic response materials, and even uniform mix them with hydrogel to prepare the required thickness of dressings. The high encapsulation efficiency can ensure sufficient dosage of the drugs and further realize the control of ultrasonic response through quantitative encapsulation of ultrasound-responsive materials. Using high frequency (5 MHz, 0.4 W cm-2 ) and low frequency (60 kHz, 1 W cm-2 ) ultrasound to control the movement and rupture of U-CMLVs, the contents not only penetrate the stratum corneum into the epidermis but also break through the bottleneck of penetration efficiency, and deep into the dermis. These findings provide the groundwork for deep, controllable, efficient, and safe drug delivery through TDDS and lay a foundation for further expanding its application.

A rational synthesis of ultrasmall palladium-based alloys with superhydrophilicity as biocompatible agents and recyclable catalysts.

As essential controlling parameters, the local surface area (size distribution) and polarity property of the surface molecules can determine the catalytic activity and biocompatibility directly. Here, ultrasmall palladium-based alloys (FePd, FePdCo, and FePdCu NCs) were developed to serve as artificial degradation catalysts with superhydrophilicity (SPh), biocompatibility, and reusability, which were referred to as "biocatalysts". As synthesized in aqueous solvent with negative surface potential while dispersing in water medium, because of the surface biological molecules effect. The obtained alloys illustrated a size distribution of about 3.5 nm. Additionally, owing to SPh property, these alloys could be stored in water up to 30 days without any precipitation and retained their monodisperse morphology in colloidal solutions. The cytotoxicity assessment of the alloys by exposing to L-929 cells over 3 days indicated that it maintained cell viability of >80% even up to 390 µg mL-1 (concentration of alloys). Furthermore, they exhibited an obvious enhancement in the catalytic performance for degrading Rhodamine B (RhB) and 4-nitrophenol (4-NP). The recyclable utilization of biocatalysts demonstrates durable stability even after 8 reduction cycles.